Internal combustion engines are widely used for power, both domestically and in industry. For instance, internal combustion engines are commonly used to power vehicles, such as passenger cars, in the automotive industry.
Corrosion can adversely affect the performance of a vehicle fuel system and engine. In particular, corrosion of ferrous metal surfaces may result in rusting or the formation of rust particles, such as due to the reaction of the metal surfaces with water that may enter the fuel system of a vehicle, for example through storage and handling of gasoline fuel. Rust particles may also enter the fuel system of the vehicle with the gasoline, for example as a result of rust corrosion in pipelines, tank trucks or while stored at terminals or retail stations.
Corrosion and rusting can impact the performance of the fuel metering pump, fuel lines and fuel injectors, amongst other components of the fuel system and engine.
Formation of particles from rusting can also impact the performance of the components of the fuel system and engine. For example, the presence of rust particles can contribute to problems of wear, clogging and/or sludge formation.
Furthermore, rust particles contribute to the blockage of fuel and/or lubricant filters, which may lead to fuel starvation, problems with pre-ignition or otherwise have an adverse effect on overall vehicle performance.
In recent years, the presence of rust particles in gasoline fuel has carried increased risk of causing difficulty to motorists. Several factors have increased the severity of the problem of corrosion and rust in particular, such as gasolines consumed by automobiles being transported through pipelines increasingly. Corrosion in pipelines can therefore lead to the gasolines transported through these pipelines to carry rust into retail station storage tanks and into consumers' vehicles. Another factor is the adoption by automobile manufacturers of gasoline fuel filters of increasing efficiency that may, having smaller pore sizes, become clogged more quickly by fine rust particles.
Common anti-rust additives include carboxylic acids, anhydrides, amines and amine salts of carboxylic acids. They typically consist of a polar head to enable adhesion to the metal surfaces to be protected, and a hydrocarbon tails responsible for solubility in fuel. These anti-rust additives may be used in addition to other additives, which each carry out a specific function. It would be desirable for an additive to be effective as an anti-rust additive, whilst also carrying out another function in the fuel.
There is a need for further methods for preventing corrosion, in particular rusting of ferrous metal surfaces and metal parts of the fuel system and engine.